Hello,
I have an early production 515a, which uses some 6U8s and 6BQ7s. At serial number 4804, Tek introduced a bunch of tweaks including replacing them with 6DJ8s. My paper manual's circuit diagrams depict the newer design, with the old components in red. I've come across a couple of mistakes in the red annotations, and also wonder if the voltage values are correct for the older design. Some of the old circuitry is omitted entirely in the new circuit diagram, for instance where in the calibrator a single 6AU6 pentode replaced the original 6U8 triode-pentode, but as far as I can tell, doesn't show the function of the 6U8's triode section.
I've searched without success for a PDF of the original 515 or pre-4804 515a schematics, without success. Do you have a 515 or early production 515a manual or PDF showing *only* the old circuits?
